Reducing potential of chemical fertilizers and scientific fertilization countermeasure in vegetable production in China

The vegetable nutrient management team of CARS-23 (China Agriculture Research System) has investigated the fertilization situation in 1227 farmers’ vegetable plots, including 578 greenhouse vegetable plots and 649 open field vegetable plots around China. The acquired data were summarized in this paper, and the problems existed were as follows, 1) The average amount of nutrient (N + P₂O₅ + K₂O) from chemical fertilizers in vegetables production was 1092.0 kg/hm², which was 3.3 times as high as that of crops in China (328.5 kg/hm²). The average chemical nutrient application in greenhouse and open field vegetable were respectively 1354.5 and 859.5 kg/hm², which were respectively 4.1 and 2.6 times as high as that of crops in our country. 2) The N, P₂O₅ and K₂O inputs from both the chemical fertilizers and organic manure were all excessive, the N, P₂O₅ and K₂O inputs in the greenhouse vegetables are respectively 1.9, 5.4, 1.6 times of those recommended, and those in the open fields were 2.7, 5.9, 1.5 times. 3) The fertilization was not balance generally in all the surveyed main vegetable production regions. The average ratio of N∶P₂O₅∶K₂O input in the total nutrients (including chemical fertilizers and organic manures), in organic manures and in basal-applied chemical fertilizers was respectively 1.00∶0.85∶0.94, 1.00∶1.10∶0.88, and 1.00∶0.95∶1.09 in the greenhouses, and 1.00∶0.63∶0.56, 1.00∶1.01∶0.84, and 1.00∶0.90∶0.67 in the open fields. P₂O₅ input was obviously too high in the total nutrient inputs (chemical fertilizers + organic manures), organic manures and basal applied chemical fertilizers. 4) The basal-applied ratio of chemical fertilizer nutrients (N + P₂O₅ + K₂O) was commonly too high in both greenhouse and open field vegetables, with the average ratio of 45.7% and 51.0%, respectively. Thereinto, the average ratio in greenhouse in North, East, Central, and Southwestern ranged from 45.5% to 68.7%, and that was as high as 63.0% in open fields in Central China. 5) For rational fertilization, in which the chemical nutrients were substituted with 45% of organic manure in greenhouse vegetable and 35% in open field vegetable, the average reduction potential of nutrients from chemical fertilizers in main greenhouse vegetables and open field vegetables was respectively 34.8%–67.1% and 41.9%–76.8%. We should pay much more attention on coordinating N∶P₂O₅∶K₂O ratio and basal-topdressing ratio of chemical fertilizers, and decreasing the P₂O₅ application ratios. In addition, developing countermeasures about the efficient technologies of chemical fertilizer reduction, chemical fertilizers substituted with organic manure, new special-purpose fertilizer application, drip fertigation technology promotion are needed.